1 /* $OpenBSD: auth.h,v 1.101 2020/12/22 00:12:22 djm Exp $ */ 2 3 /* 4 * Copyright (c) 2000 Markus Friedl. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 */ 27 28 #ifndef AUTH_H 29 #define AUTH_H 30 31 #include <signal.h> 32 33 #ifdef HAVE_LOGIN_CAP 34 #include <login_cap.h> 35 #endif 36 #ifdef BSD_AUTH 37 #include <bsd_auth.h> 38 #endif 39 #ifdef KRB5 40 #include <krb5.h> 41 #endif 42 43 struct passwd; 44 struct ssh; 45 struct sshbuf; 46 struct sshkey; 47 struct sshauthopt; 48 49 typedef struct Authctxt Authctxt; 50 typedef struct Authmethod Authmethod; 51 typedef struct KbdintDevice KbdintDevice; 52 53 struct Authctxt { 54 sig_atomic_t success; 55 int authenticated; /* authenticated and alarms cancelled */ 56 int postponed; /* authentication needs another step */ 57 int valid; /* user exists and is allowed to login */ 58 int attempt; 59 int failures; 60 int server_caused_failure; 61 int force_pwchange; 62 char *user; /* username sent by the client */ 63 char *service; 64 struct passwd *pw; /* set if 'valid' */ 65 char *style; 66 67 /* Method lists for multiple authentication */ 68 char **auth_methods; /* modified from server config */ 69 u_int num_auth_methods; 70 71 /* Authentication method-specific data */ 72 void *methoddata; 73 void *kbdintctxt; 74 #ifdef BSD_AUTH 75 auth_session_t *as; 76 #endif 77 #ifdef KRB5 78 krb5_context krb5_ctx; 79 krb5_ccache krb5_fwd_ccache; 80 krb5_principal krb5_user; 81 char *krb5_ticket_file; 82 char *krb5_ccname; 83 #endif 84 struct sshbuf *loginmsg; 85 86 /* Authentication keys already used; these will be refused henceforth */ 87 struct sshkey **prev_keys; 88 u_int nprev_keys; 89 90 /* Last used key and ancillary information from active auth method */ 91 struct sshkey *auth_method_key; 92 char *auth_method_info; 93 94 /* Information exposed to session */ 95 struct sshbuf *session_info; /* Auth info for environment */ 96 }; 97 98 /* 99 * Every authentication method has to handle authentication requests for 100 * non-existing users, or for users that are not allowed to login. In this 101 * case 'valid' is set to 0, but 'user' points to the username requested by 102 * the client. 103 */ 104 105 struct Authmethod { 106 char *name; 107 int (*userauth)(struct ssh *); 108 int *enabled; 109 }; 110 111 /* 112 * Keyboard interactive device: 113 * init_ctx returns: non NULL upon success 114 * query returns: 0 - success, otherwise failure 115 * respond returns: 0 - success, 1 - need further interaction, 116 * otherwise - failure 117 */ 118 struct KbdintDevice 119 { 120 const char *name; 121 void* (*init_ctx)(Authctxt*); 122 int (*query)(void *ctx, char **name, char **infotxt, 123 u_int *numprompts, char ***prompts, u_int **echo_on); 124 int (*respond)(void *ctx, u_int numresp, char **responses); 125 void (*free_ctx)(void *ctx); 126 }; 127 128 int 129 auth_rhosts2(struct passwd *, const char *, const char *, const char *); 130 131 int auth_password(struct ssh *, const char *); 132 133 int hostbased_key_allowed(struct ssh *, struct passwd *, 134 const char *, char *, struct sshkey *); 135 int user_key_allowed(struct ssh *, struct passwd *, struct sshkey *, int, 136 struct sshauthopt **); 137 int auth2_key_already_used(Authctxt *, const struct sshkey *); 138 139 /* 140 * Handling auth method-specific information for logging and prevention 141 * of key reuse during multiple authentication. 142 */ 143 void auth2_authctxt_reset_info(Authctxt *); 144 void auth2_record_key(Authctxt *, int, const struct sshkey *); 145 void auth2_record_info(Authctxt *authctxt, const char *, ...) 146 __attribute__((__format__ (printf, 2, 3))) 147 __attribute__((__nonnull__ (2))); 148 void auth2_update_session_info(Authctxt *, const char *, const char *); 149 150 #ifdef KRB5 151 int auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client, krb5_data *); 152 int auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt); 153 int auth_krb5_password(Authctxt *authctxt, const char *password); 154 void krb5_cleanup_proc(Authctxt *authctxt); 155 #endif /* KRB5 */ 156 157 #if defined(USE_SHADOW) && defined(HAS_SHADOW_EXPIRE) 158 #include <shadow.h> 159 int auth_shadow_acctexpired(struct spwd *); 160 int auth_shadow_pwexpired(Authctxt *); 161 #endif 162 163 #include "auth-pam.h" 164 #include "audit.h" 165 void remove_kbdint_device(const char *); 166 167 void do_authentication2(struct ssh *); 168 169 void auth_log(struct ssh *, int, int, const char *, const char *); 170 void auth_maxtries_exceeded(struct ssh *) __attribute__((noreturn)); 171 void userauth_finish(struct ssh *, int, const char *, const char *); 172 int auth_root_allowed(struct ssh *, const char *); 173 174 char *auth2_read_banner(void); 175 int auth2_methods_valid(const char *, int); 176 int auth2_update_methods_lists(Authctxt *, const char *, const char *); 177 int auth2_setup_methods_lists(Authctxt *); 178 int auth2_method_allowed(Authctxt *, const char *, const char *); 179 180 void privsep_challenge_enable(void); 181 182 int auth2_challenge(struct ssh *, char *); 183 void auth2_challenge_stop(struct ssh *); 184 int bsdauth_query(void *, char **, char **, u_int *, char ***, u_int **); 185 int bsdauth_respond(void *, u_int, char **); 186 187 int allowed_user(struct ssh *, struct passwd *); 188 struct passwd * getpwnamallow(struct ssh *, const char *user); 189 190 char *expand_authorized_keys(const char *, struct passwd *pw); 191 char *authorized_principals_file(struct passwd *); 192 193 FILE *auth_openkeyfile(const char *, struct passwd *, int); 194 FILE *auth_openprincipals(const char *, struct passwd *, int); 195 int auth_key_is_revoked(struct sshkey *); 196 197 const char *auth_get_canonical_hostname(struct ssh *, int); 198 199 HostStatus 200 check_key_in_hostfiles(struct passwd *, struct sshkey *, const char *, 201 const char *, const char *); 202 203 /* hostkey handling */ 204 struct sshkey *get_hostkey_by_index(int); 205 struct sshkey *get_hostkey_public_by_index(int, struct ssh *); 206 struct sshkey *get_hostkey_public_by_type(int, int, struct ssh *); 207 struct sshkey *get_hostkey_private_by_type(int, int, struct ssh *); 208 int get_hostkey_index(struct sshkey *, int, struct ssh *); 209 int sshd_hostkey_sign(struct ssh *, struct sshkey *, struct sshkey *, 210 u_char **, size_t *, const u_char *, size_t, const char *); 211 212 /* Key / cert options linkage to auth layer */ 213 const struct sshauthopt *auth_options(struct ssh *); 214 int auth_activate_options(struct ssh *, struct sshauthopt *); 215 void auth_restrict_session(struct ssh *); 216 int auth_authorise_keyopts(struct ssh *, struct passwd *pw, 217 struct sshauthopt *, int, const char *); 218 void auth_log_authopts(const char *, const struct sshauthopt *, int); 219 220 /* debug messages during authentication */ 221 void auth_debug_add(const char *fmt,...) 222 __attribute__((format(printf, 1, 2))); 223 void auth_debug_send(struct ssh *); 224 void auth_debug_reset(void); 225 226 struct passwd *fakepw(void); 227 228 int sys_auth_passwd(struct ssh *, const char *); 229 230 #if defined(KRB5) && !defined(HEIMDAL) 231 krb5_error_code ssh_krb5_cc_gen(krb5_context, krb5_ccache *); 232 #endif 233 234 #endif /* AUTH_H */ 235